The invention relates to an electric-motor furniture drive having a power supply device for adjusting movable furniture components relative to one another.
Such electric-motor furniture drives are known in various embodiments. They are implemented as linear drives having a linearly adjustable output element or as rotational drives having a rotating output element and have proven themselves extremely well in practice. The linear drives have one or a number of electric motors, wherein a speed reduction gear is connected downstream from each motor and a further gear, for example, in the form of a threaded spindle gear, is connected downstream from the speed reduction gear, which further gear generates a linear movement of the output element from the rotational movement of the motor. The rotational drives have at least one speed reduction gear connected downstream from the respective electric motor, wherein the last gearing element forms the output gear. The output element of the respective electric-motor furniture drive is connected to a fixed furniture component and/or to a movable furniture component, so that the movable furniture components are adjusted relative to one another in the event of operation of the electric motor. The furniture can be implemented as a slatted frame, worktable, bed, recombinant surface, treatment couch, hospital or healthcare bed, and also a lifting device for persons such as lifters or patient lifters.
Switched power supplies have proven themselves best as the power supply devices for operating the electric-motor furniture drives. The power supply device has an operating state “off” in the event of disconnection from the network and an operating state “operation” in regular operation. The switched power supplies have a isolation transformer switched at high frequency by a control module, which can also be designated as a transformer or as a high-frequency transformer, which is turned on and off by an upstream semiconductor switch on the primary side at a high switching frequency. For this purpose, a separate intermediate circuit is assigned to the control module, which has a power source of the control module and supplies the control module with electrical power.
Document DE 10 2006 049 715 A1 illustrates a power supply for motorized drives, which is implemented in a plug housing as a switched power supply.
The prior art of a network circuit breaker or a higher-order network circuit breaker will also be discussed. The network circuit breaker, e.g., of an apartment, is introduced between the apartment installation and the public power supply network and detects whether an electrical consumer, e.g., a light, is switched on or off. The apartment installation means the electrical wiring of the apartment for the network voltage. When an electrical consumer is no longer still turned on, the network circuit breaker disconnects the apartment installation from the public power supply network. The network circuit breaker then generates a test voltage, e.g., a harmless DC voltage of a specific level, and switches it to the apartment installation. If a consumer is now switches on, it recognizes the test voltage and causes the network circuit breaker to connect the apartment installation to the public power supply network again. Such a network circuit breaker can also be used regionally or respectively for a room.